1. Field of the Invention
This invention relates to a fiber optic detector for measuring the relative coal to ash forming impurities content in the tailings of a froth flotation process to monitor the frother addition rate to optimize the coal removal in the flotation cell.
2. Summary of the Prior Art
Various methods and apparatus have been employed to control the operating parameters of flotation cells including the addition of frother additives to the cells to optimize the removal of coal in the cell. In this process, impurities such as ash forming minerals which are the unwanted impurities are separated from the combustible materials (coal). One such device is illustrated in U.S. Pat. No. 4,552,651 which discloses a device for measuring the pulp density in the cell to control cell operation. Another conventional method of controlling cell operation is through the visual observation of the hue of gray in the tailings from the cell. A light gray color will indicate a high impurities content and a darker gray will be indicative of a high coal content in the tailings. This visual inspection by the operator and subsequent manual manipulation of the addition of frother to the cell to optimize coal removal is subject to the obvious disadvantage of inconsistency of control and human error.
Other devices such as nuclear densitometers, coriolis effect mass flow detectors, magnetic flowmeters, dual bubbler tube densitometers and X-ray diffraction equipment have been used to monitor the flotation process, however, these devices are complicated and expensive and do not provide a simple physical reading of the coal content in the tailings from the cell to monitor cell operation.
It is, therefore, desirable to obtain a method and apparatus for automatically measuring the flotation tailings for coal content to control the frother addition rate to the flotation cell to optimize coal removal from the cell.